Kinetic Study of Ethyl Hexanoate Synthesis Using Surface Coated Lipase from Candida Rugosa

Abstract

<em>Kinetics of lipase-catalyzed esterification of hexanoic acid and ethyl alcohol using the solvent-free system, surface coated lipase from Candida rugosa, had been studied. The effect of various parameters such as reaction time, reaction temperature, reaction kinetics, water removal and feasibility of solvent-free system had been focused. Candida Rugosa lipase was more effective than other lipases when ethyl hexanoate was synthesized in n-hexane. The highest esterification yield after 72 h (93 %) was achieved at a pH of 5.2 and the esterification yield was reduced to 73% at pH 4.0. The values of the apparent kinetic parameters were computed as <em>V</em>_max= 0.146 μmol/min/mg enzyme; <em>K</em>_{M, Acid}= 0.296 M; <em>K</em>_{M, Alcohol}= 0.1388 M; <em>K</em>_{i, Acid}= 0.40 M; and <em>K</em>_{i, Alcohol}= 0.309 M. The reaction rate could be described in terms of the Michaelis–Menten equation with a Ping-Pong Bi-Bi mechanism and competitive inhibition by both the substrates.</em>